From 63ae52502d16296bcce9b0d0672a95aa2ef6804b Mon Sep 17 00:00:00 2001
From: Nick Cipollo <njc1115@gmail.com>
Date: Mon, 14 Oct 2024 15:55:09 -0400
Subject: [PATCH] Add initial container

---
 Sources/WhoopDIKit/Container/Container.swift | 114 +++++++++++++++++++
 1 file changed, 114 insertions(+)
 create mode 100644 Sources/WhoopDIKit/Container/Container.swift

diff --git a/Sources/WhoopDIKit/Container/Container.swift b/Sources/WhoopDIKit/Container/Container.swift
new file mode 100644
index 0000000..1eea632
--- /dev/null
+++ b/Sources/WhoopDIKit/Container/Container.swift
@@ -0,0 +1,114 @@
+import Foundation
+public final class Container {
+    private let serviceDict = ServiceDictionary<DependencyDefinition>()
+    private var localServiceDict: ServiceDictionary<DependencyDefinition>? = nil
+
+    /// Registers a list of modules with the DI system.
+    /// Typically you will create a `DependencyModule` for your feature, then add it to the module list provided to this method.
+    public func registerModules(modules: [DependencyModule]) {
+        modules.forEach { module in
+            module.defineDependencies()
+            module.addToServiceDictionary(serviceDict: serviceDict)
+        }
+    }
+
+    /// Injects a dependency into your code.
+    ///
+    /// The injected dependency will have all of it's sub-dependencies provided by the object graph defined in WhoopDI.
+    /// Typically this should be called from your top level UI object (ViewController, etc). Intermediate components should rely upon constructor injection (i.e providing dependencies via the constructor)
+    public func inject<T>(_ name: String? = nil, _ params: Any? = nil) -> T {
+        do {
+            return try get(name, params)
+        } catch {
+            print("Inject failed with stack trace:")
+            Thread.callStackSymbols.forEach { print($0) }
+            fatalError("WhoopDI inject failed with error: \(error)")
+        }
+    }
+
+    /// Injects a dependency into your code, overlaying local dependencies on top of the object graph.
+    ///
+    /// The injected dependency will have all of it's sub-dependencies provided by the object graph defined in WhoopDI.
+    /// Typically this should be called from your top level UI object (ViewController, etc). Intermediate components should rely
+    /// upon constructor injection (i.e providing dependencies via the constructor).
+    ///
+    /// This variant allows you to provide a local module definition which can be used to supply local dependencies to the object graph prior to injection.
+    ///
+    /// Example:
+    /// ```swift
+    /// let localDependency = MyLocalDependency()
+    /// let myObject: MyObject = WhoopDI.inject { module in
+    ///     module.factory { localDependency as LocalDependency }
+    /// }
+    /// ```
+    ///
+    /// - Parameters:
+    ///   - name: An optional name for the dependency. This can help disambiguate between dependencies of the same type.
+    ///   - params: Optional parameters which will be provided to dependencies which require them (i.e dependencies using defintiions such as
+    ///   (factoryWithParams, etc).
+    ///   - localDefinition: A local module definition which can be used to supply local dependencies to the object graph prior to injection.
+    /// - Returns: The requested dependency.
+    public func inject<T>(_ name: String? = nil,
+                          params: Any? = nil,
+                          _ localDefinition: (DependencyModule) -> Void) -> T {
+        guard localServiceDict == nil else {
+            fatalError("Nesting WhoopDI.inject with local definitions is not currently supported")
+        }
+        // We need to maintain a reference to the local service dictionary because transient dependencies may also
+        // need to reference dependencies from it.
+        // ----
+        // This is a little dangerous since we are mutating a static variable but it should be fine as long as you
+        // don't use `inject { }` within the scope of another `inject { }`.
+        let serviceDict = ServiceDictionary<DependencyDefinition>()
+        localServiceDict = serviceDict
+        defer {
+            localServiceDict = nil
+        }
+
+        let localModule = DependencyModule()
+        localDefinition(localModule)
+        localModule.addToServiceDictionary(serviceDict: serviceDict)
+
+        do {
+            return try get(name, params)
+        } catch {
+            fatalError("WhoopDI inject failed with error: \(error)")
+        }
+    }
+
+    /// Used internally by the DependencyModule get to loop up a sub-dependency in the object graph.
+    func get<T>(_ name: String? = nil,
+                _ params: Any? = nil) throws -> T {
+        let serviceKey = ServiceKey(T.self, name: name)
+        let definition = getDefinition(serviceKey)
+        if let value = try definition?.get(params: params) as? T {
+            return value
+        } else if let injectable = T.self as? any Injectable.Type {
+            return try injectable.inject() as! T
+        } else  {
+            throw DependencyError.missingDependecy(ServiceKey(T.self, name: name))
+        }
+    }
+
+    /// Used internally via the `WhoopDIValidator` to verify all definitions in the object graph have definitions for their sub-dependencies  (i.e this verifies the object graph is complete).
+    func validate(paramsDict: ServiceDictionary<Any>, onFailure: (Error) -> Void) {
+        serviceDict.allKeys().forEach { serviceKey in
+            let definition = getDefinition(serviceKey)
+            do {
+                let _ = try definition?.get(params: paramsDict[serviceKey])
+            } catch {
+                onFailure(error)
+            }
+        }
+    }
+
+    private func getDefinition(_ serviceKey: ServiceKey) -> DependencyDefinition? {
+        return localServiceDict?[serviceKey] ?? serviceDict[serviceKey]
+    }
+
+    public func removeAllDependencies() {
+        serviceDict.removeAll()
+    }
+}
+
+